Apparatus for heating and mixing paving materials



March 29, 1955 H. A. BARBER EIAL 2,705,133

APPARATUS FOR HEATING AND MIXING PAVING MATERIALS Filed Nov. 13, 1951 4 Sheets-Sheet l .[HVE'HL 02 5 I 51 w M2055- e-zwr LL55 March 29, 1955 'H. A. BARBER EI'AL 2,705,133

APPARATUS FOR HEATING AND MIXING PAVING MATERIALS Filed Nov. 13, 1951 4 Sheets-Sheet 2 Q March 29, 1955 H. A. BARBE R EI'AL 2,705,133

APPARATUS FOR HEATING AND MIXING PAVING MATERIALS Filed Nov. 13, 1951 4 Sheets-Sheet 3 Brace/112065 March 29, 1955 H. A. BARBER ETAL I 2,705,

APPARATUS FOR HEATING AND MIXING PAVING MATERIALS Filed Nov. 13, 1951 Y 4 Sheets-Sheet 4 Q 3 O I x 3 & 1 R

. I; N I s ,W EVE'JIZURW LR,- fjJzYg A Barber h V .ErzzaeM/fasas dlkwfizzyfi APPARATUS FOR HEATING AND MIXING PAVING MATERIALS Harry A. Barber, Aurora, and Bruce M. Ross, Batavia, Ill., assignors to Barber-Greene Company, Aurora, 111., a corporation of Illinois Application November 13, 1951, Serial No. 256,025 4 Claims. (Cl. 259156) This invention relates to a method of and an apparatus for heating and mixing paving materials and more particularly to a compact portable batch plant for treating and mixing an aggregate with a bituminous cement prod uct and a method of treating and combining an aggregate with a bituminous cement product.

Although the method and apparatus of this invention may be used for other Portland cement in cold adapted for making a batch of aggregate such as crushed stone or gravel and a bituminous cement such as asphalt. Heretofore it has been the practice in the laying of bituminous pavement to use conportation from place to place.

According to this invention, a compact and portable batch plant is provided which includes a hopper station for receiving the exact quantity and character of the aggregate desired, a drying station that can be readily adjusted in accordance with the volume and moisture content of the aggregate and the desired final temperature of the aggregate, and a mixer for receiving aggregate discharge from the drying station and for receiving a quantity of the bituminous cement product according to the quantity of aggregate.

important feature of this invention is in the drying station which herein includes a pair of spaced, generally vertical walls forming a part of the frame of the machine and a roller-mounted drier drum disposed between the walls for rotation about a generally horizontal axis. The drier drum has internal, inwardly projecting blades adapted to circulate aggregate therewithin. A combustion chamber is supported between the walls and within the drum and is arranged to direct heated gases into the path of the aggregate circulated within the drum. It will be apparent that, with this arrangement, the drying station is very compact and, at the same time, is highly eflicient in that the heat from the fuel is developed within the drum and the aggregate can be quickly heated to the desired temperature.

The forward wall of the drying station is provided with a hinged door and a scoop forming the hopper station is normally positioned closely adjacent the ground or supporting surface for the machine to receive the desired quantity of aggregate therein and is movable upwardly to discharge its contents through the door in the forward wall of the drier station and into the drier drum. The mixer or pug mill is mounted on the rearward wall of the drier station at an intermediate elevation such that the contents thereof may be readily discharged by gravity directly into a wheelbarrow or the like wi an aggregate-conveying chute located thereabove, the chute being movable to within the drier drum and into the path of the aggregate circulated within the drum.

A feature of this invention is the provision of heating jackets on the mixer or pug mill for preventing cooling mixing. Ducts are provided he- An engine for operating the drier drum, the scoop is preferably mounted on the machine. For compactness, the engine is ed at one side of the scoop while a fuel mounted at the other side of the scoop.

important feature of this invention resides in the fact that the temperature of the ultimate product can be determined by the number of drum turns.

stat1on of this invention that with a given quantity of aggregate, having a given the mixer and frame of the herein mountsupply tank is used to determine the temperature of the aggregate from the moisture content and the number of drum turns.

An ob ect of this invention, accordingly, is to provide an 1mproved method of making a batch of paving matertral from an aggregate and a bituminous cement produc Another object of this invention is to provide a compact, portable batch plant for treating and mixing an aggregate with a bituminous cement product.

Other ob ects, features and advantages of this invenaccompanying bodiment and Figure 1 is a top plan view of a compact, portable batch plant constructed according to this invention;

Figure 2 is a side elevational view of the batch plant of Figure 1;

Figure 3 is an outline view illustrating plant may be mounted on a platform to a truck;

F1gure 4 is a perspective view of the batch plant of Figure 3 with certain parts broken away to show the construction of the interior of the drum and the combustion chamber; and Figure 5 is a somewhat diagrammatic illustration of the drive from the engine to the various parts of the machine.

In general, the batch plant constructed according to this invention as illustrated includes a hopper station generally designated by reference numeral 10, a drying station generally designated by reference numeral 11, a mixing station generally designated by reference numeral 12.

The hopper station 10 includes a scoop-like member 14 which is adapted to receive the desired quantity of aggregate and may be elevated by ropes 15 to a position in which the contents thereof are discharged into the drying station 11.

how the batch discharge into inwardlywhich elevate e aggregate circulated with- It will be apparent that all of the inpartrcles of the aggregate within the drum 18 are passed through the path of the heated gases from the heating and drying of burner assembly 20 so that a fast, uniform and eflicient the aggregate is achieved.

The heated gases in the drum 18 may pass through an upper opening 24 and through lower openings 25 an 26 in the rearward end wall 17, as shown in Figure 4. The upper opening 24 communicates with an upwardly mill 12.

To transfer the heated aggregate from the drying station 11 to the mixer or pug mill 12, a pivotal chute 30 is provided. To pivotally support the chute 30 on the wall 17, a pair of plates 31 are secured to the side walls of the chute 30 and each of the plates 31 is pivotally secured between a pair of angle brackets 32 secured to the inner surface of the wall 17, as illustrated in Figure 4. The chute 30 is normally in the position illustrated in Figures 1, 2 and 4 of the drawings in which it is out of the path of aggregate circulated within the drum 18 and in which the bottom and the sides thereof form the bottom and sides of the chimney 27 to direct gases from within the drum out through the ch'mney. When it is desired to transfer the heated aggregate from the drum 18 to the pug mill 12, the chute 30 may be pivoted from the position illustrated in the drawings to a position as illustrated in broken lines, Figure 2, in which the aggregate drops from the internal blades 19 of the drum onto the chute 30 and flows by gravity into the pug mill 12. One side of the chute 30 (the right-hand side, Figure 4) has a forward portion 30:: of reduced height so as not to interfere with the transfer of aggregate from the blades 19 to the chute.

To pivot the chute 30, a crank 34 has a shaft portion 34:: rotatably journaled in brackets 35 secured to the wall 17 and an arm 36 secured to the shaft portion 34a is connected through a link 37 to the chute 30.

As shown in Figure 1, the pug mill 12 has a pair of rotatable shafts 38 and 39 journaled therein and blades 40 secured to the shafts are arranged to mix the aggregate with the melted bituminous cement, the shafts 38 and 39 preferably being rotated in opposite directions. It will be understood that the bituminous cement product is normally heated in a separate kettle or cauldron. The pug mill 12 has a slidable bottom 41 arranged to be actuated to release the materials from the pug mill. To actuate the bottom, a crank 42 is provided which has a pinion 43 secured thereto and meshed with a rack 44 secured to the slidable bottom 41.

To heat the pug mill 12, a pair of heating jackets 45 and 46 are secured on either side thereof, the ducts 28 and 29 from the rear wall 17 of the drying station 11 communicating with the jackets 45 and 46, respectively. A pair of chimneys 47 and 48 extend upwardly from the jackets 45 and 46 to vent the gases to the atmosphere. The chimneys 47 and 48 may be secured together and to the chimney 27 by a plate 49. It will thus be apparent that the heated gases developed within the drying station 11 serve not only to heat the aggregate but also to heat the pug mill 12 so as to prevent solidification of the materials within the pug mill.

The pug mill 12, the drum 18 and the scoop 14 are operated from an engine 50 having an output drive shaft 51. Referring to Figure 5, the drive shaft 51 of the engine 50 has a pulley 52 secured thereto which drives a pulley 53 of a gear box 54 through belts 55. The gear box 54 has an output shaft 56 on which a pair of drive rollers 57 and 58 are mounted, the rollers 57 and 58 being in supporting and driving relation to the drier drum 18. The shaft 56 also has a pair of sprocket wheels 59 and 60 secured thereto. The sprocket Wheel 59 is connected by a chain 61 to a sprocket wheel 62 secured to a shaft 63, the shaft 63 having a pair of drum sup porting and driving rollers 64 and 65 secured thereto and in spaced relation. The sprocket wheel 60 is connected by a chain 66 to a sprocket wheel 67 secured to the shaft 38 of the pug mill 12. The other end of the shaft 38 has a gear 68 secured thereto and meshed with a like gear 69 secured to the other shaft 39 of the pug mill 12, the shafts 38 and 39 thereby being rotated in opposite directions.

For actuating the scoop 14, a sheave 70 is mounted on the roller-supporting shaft 63 and is arranged to be connected in driving relation to the shaft 63 by means of a clutch 71. The sheave 70 is connected through a rope 72 to a pulley 73 which is mounted on a shaft 74. The shaft 74 is journaled in brackets 75 and 76 secured to the forward wall 16 as shown in Figures 1 and 2. pair of pulleys 77 and 78 are secured to the shaft 74, the ropes 15 being connected to the pulleys 77 and 78 so that when the sheave 70 is clutched to the shaft 63 the pulleys 77 and 78 will be rotated through the rope 72 and pulley 73 to raise the scoop 14 and discharge the contents of the scoop through the door in the front wall 16 and into the drum 18. When the clutch 71 is disengaged, the sleave 70 will be free to rotate on the shaft 63 and the scoop 14 will be retracted to the position of Figure 2 by gravity.

For efficient combustion within the drum 18, a forced draft is preferably provided which is herein achieved from a blower 80, Figure 5, driven from the pulley 53 by means of pulleys 81 and 82 and rope 83. The blower 80 has a discharge 81 connected through pipes including pipe 82, Figure 2, to the burner assembly 20.

A feature of this invention is in the manner in which the components of the machine are supported for compactness, operating convenience, portability, durability and ease of manufacture and assembly. All of the component parts of the machine are mounted on a frame generally designated by reference numeral 84 which, in turn, is supported at one end by a pair of wheels 85 and 86 and at the other end by a retractible pivotal post 87 when the machine is stationary or from a truck or tractor through a coupling 88.

The engine 50 and a fuel supply tank 89 are mounted on the frame 84 forward from the wheels 85 and 86 with the scoop 14 positioned therebetween. The forward wall 16 of the drying station 11 is secured to the frame 84 at its far end and has its upper end secured to the frame through a pair of brace rods 91 and 92. The rearward wall 17 of the drying station is likewise secured to the frame 84 at its lower end, the upper end thereof being secured to the forward wall 16 through a pair of overhead frame members 93 and 94. Thus the walls 16 and 17 are securely fastened to the frame spaced relation. To pivotally support the scoop 14 from the forward wall 16, a pair of 5 and 96 are secured thereto and pivoted on a shaft 97 which is secured between spaced brackets 98 and 99 on the forward wall 16.

The pug mill 12 is supported from the rearward wall 17 by lower brackets 101 and upper brace rods 102.

It will be noted that the scoop 14 in its material-receiving position is very close to the ground or supporting surface for the machine so that the aggregate or other material may be readily placed therein, no elevator or other apparatus being required. It will be also noted that the scoop 14 discharges directly into the drum and that the material may be discharged directly from the drum through the chute 30 to the pug mill 12, the pug mill 12 being at a substantial elevation above the ground or supporting surface for the machine so that the contents thereof may be discharged by gravity to a wheelbarrow or whatever hauling apparatus may be used in conjunction with the machine. As illustrated in Figure 3, the machine may be mounted on a platform 103 to discharge directly into a truck 104.

Although the plant may be used other purposes, such as for the mixing of Portland cement in freezing temperatures, for example, it is peculiarly and particularly adapted for preparing and mixing an aggregate such as sand or gravel with a bituminous product such as asphalt.

In operation, a quantity of sand or gravel or other aggregate is placed in the scoop 14. With the burner 22 ignited and the engine 50 running, the clutch 71 is engaged to raise the scoop 14 and discharge the aggregate from the scoop through the swinging door in the wall 16 and into the drum 18. The aggregate is then circulated by the blades 19 with rotation of the drum so as to pass through the heated gases from the burner 22. The aggregate is left in the drum for a number of drum turns, depending upon the quantity, the moisture content and the desired temperature.

As an example of a typical operation with a particular machine, with the drier drum turning at S R. P. M., the burner operating with 12 lbs. oil pressure, 1 /2 lbs. air pressure and burning 10 gallons of No. 2 diesel fuel oil per hour, 3 cubic feet of graded gravel with 4% moisture content is heated to 300 F. in 12. drum revolutions or advantageously for approximately 2 /2 minutes. By running anumber of tests 3. In a material heating and mixing plant, in combi-- on a particular machine, a chart, or a series of charts, nation, a frame, a pair of spaced upright stationary walls example, are constant.' tion of said drum, a burner supported between said walls Due to the uniform heating and drying action obtained and within the drum having a burner discharge below by the drum and burner assembly of this invention, even the drum axis projecting heated gases into said drum in the most unskilled of operators can readly obtain the the central portion thereof below the drum axis, a mixer kettle or cauldron carried along on the job. After the municating with each of said jackets and extending and release the mixed aggregate and asphalt to fall diand flues mounted on each of said jackets to permit the rectly to the roadway surface or into a wheelbarrow or passage of heated gases through said jackets.

the like. 4. In a material heating and mixing plant, in combina- It will be understood that modifications and variations tion, a frame, a pair of spaced upright stationary walls may be effected without departing from the spirit and on said frame, an annular rotatable drum disposed and scope of the novel concepts of this invention. encompassing the space between said walls and having We claim as our invention: internal, inwardly projecting blades to elevate the material 1. In a material heating and mixing plant, in combiand release the material to fall through a central portion nation, a frame, a pair of spaced upright stationary walls of said drum, a burner supported between said walls andsupported on one of said walls, a chutepivotally mounted mounted in the aperture and having a receiving end swingwall above the burner discharge to conduct heated gases d w separate ducts communicajillg with each of nation, a frame, a pair of spaced upright statronary walls Said j encompassing Ellie space betwteerll said galls and havin References Cited in the file of this patent interna inwar y projecting la es to e evate the material and release the material to fall through a central por- UNITED STATES PATENTS tion of said drum, a burner supported between said walls 851,686 Mulr et al. Apr. 30, 1907 and Within the drum having a burner discharge below the 1,171,583 Benson Feb. 15, 1916 drum axis projecting heated gases into said drum in the 1,716,920 Grohens June 11, 1929 central portion thereof below the drum axis, a mixer sup- 2,305,938 Trumbull Dec. 22, 1942 ported on one of said walls, a chute pivotally mounted ,60 2,344,307 Jones Mar. 14, 1944 on said one wall for discharging material from said drum 2,397,581 Waters Apr. 2, 1946 into said mixer, said mixer having an open top and side, 2,437,395 Magmlsson 6t M311 1943 bottom and end walls defining a mixing chamber, opposed 2,492,792 0rd Dec. 27, 1949 heating jackets mounted on oppgsite rgixefr side wills, 2,504,378 Bell Apr. 18, 1950 separate ucts communicating wi eac 0 said jac ets and extending through said one wall above the burner FOREIFHTI PATENTS discharge to conduct heated gases from within the drum 18,355 Great Brrtam Aug. 5, 1915 to said jackets and flues mounted on each of said jackets 470,590 Germany Jan. 21, 1929 

